Annealing equipment and method



Sept. 3, 1929. T. F. BAILY ANNEALING EQUIPMENT AND METHOD Filed Aug. 20, 1926 3 Sheets-Sheet 1 gwwntoz atto: new

Sept. 3, 1929. T. F. BAILY ANNEALING EQUIPMENT AND METHOD Filed Aug. 20, 1926 3 Sheets-Sheet 2 sept. 3, 192.9. T. F. BAILY' 1,727,192

ANNEALING EQUIPMENT AND METHOD Filed Aug. 20, 1926 3 Sheets-Sheet 5 @H601 new Patented Sept. 3, 192,9.

l THADDEUB l'. BAILY, 0F ALLIANCE, OIHIO.

ANNEALING EQUIPMENT AND METHOD.

Application tiled August 20, 1928. Serial No. 130,521.

This invention relates to the circulating of heating and cooling gases throu-gh annealing hoods and the like and more particularly to the annealing of metal articles.

The objects of the improvement arev to provide means whereby gas is circulated through heating or coolin chambers extraneous to the annealing hoo and then through the annealing hood containing the material under treatment, therebiy controlling the temperature of the materia ing and cooling; means being provided for regulating the iow of the heated and cooled gases through the hood.

l5 A further object of the improvement is to provide an eicient annealing hood and the like adapted to be quickly brought to the desired temperature, the same comprising an inner shell of high heat resisting metal, a spaced outer shell of steel or the like and a illei` of silocel or other suitable heat insulating material being provided between the inner and outer shells. l

Another object of the improvement is to provide a fan for circulating the heated gases, the impeller of said fan and the inner casing being formed of high heat resisting metal, whereby the impeller will resist the strains induced by the centrifugal action of the fan; 30. and provided with a shaft of the same material extended through a heat insulated wall in the duet leading from the heating chamber to the hood; said duct being preferably made with an inner surface of heat resisting metal and provided on the outside with a heat insulating material. 4

Another object of the invention is to provide a plurality of hoods particularly adapted to slowly heat, soak and cool and arranged in a series so'that only one hood is heating at any one time, thus enabling' the heating means tov be operated in its most economical manner both as to even power load and to prevent idle capacity.

The advantages of this type of equipment over the usual equipment for annealing similar materials are, the close control of the heating, soaking and cooling cycle, since the direct heatingmedium is a reducing or nonoxidizing gas passing-directly in and around the material to be annealed, the materialbeing heated not byradiation only, as in the case of all other electric furnaces; secondly, simplicity of handling the material, as in the type of equipment disclosed the material and the rate of heatmay be placed in racks and by means of a crane placed upon the heating pedestal and the hood or cover placed over the pack and pedestal by means of the crane.

An embodiment of the invention is illustrated in the accompanying drawings, in which Figure 1 is a diagrammatic plan view showing a plurality of annealing hoods connected l with the heating and cooling means;

Fig. 2, a plan sectional view of a single hood showing the connection of the same to the heating means;

Fig. 3, a transverse sectional view taken substantially on the line 3 3, Fig. 2;

Fig. 4, a transverse sectional view through one of the pedestals designed for use in connection with both heating and cooling means, an

Fig. 5, a diagrammatic view of the damper control mechanism for one hood.

Similar numerals v refer to similar part throughout the drawings.

The material supporting pedestal 1 or 1"L is arranged to be permanently located in any suitable position upon the floor and may be provided with a single channel 2 in the event it is to be connected only to the heating means, or with a pair of spaced channels 2 if it is to be connected with the heating and cooling means both.

`The invention is capableof many different uses but is especially applicable to the annealing of tubes, bars and the like which require soaking at high temperatures for con` siderable periods and slowcooling. A

In the accompanying drawings the invention is illustrated as a pliedto the annealing of tubes 3 which mayle formed into a pack, within a cradle or rack 4 and lowered upon the pedestal by means of a crane or the like.

The hoods, indicated generally at 5, are e lthen lo/wered by the crane and laced over the pdestals and packs as best il ustrated in Fig. 3. Each of these hoods preferably comprises an inner shell or lining 6 of high heat resisting metal such as chromium, and aspaced outer shell or casing 7 which may be heavy sheets or plates of steel.

The inner and outer shells are connected in spaced relation by means of the angles 8,v channels 9 which enter the sand troughs 10, forming a sand seal, around the hood, and the bolts 11, suitable heat insulating material, such as silocel or the like, being interposed y between the shells as shown at 12. This con- Heat is preferably furnished to the heating chamber by means of the electric resistance element 18. The bottom Wall 19 of the heating chamber is provided at opposite ends with the channels 20 which communicate with ducts 2l and 22 leading to opposite ends of the pedestal and communicating with the channels 2 therein.

These ducts are also preferably formed in the same manner as the hood and heating chamber, having the inner lining 23 of high heat resisting metal, surrounded by the heat insulating material 24, and preferably covered by a casing 25, which may be of any suitable material.

For the purpose of circulating a reducing or non-oxidizing gas through the heating chamber and hood, in a continuous closed circuit, a fan may be located in the duct 22, the impeller 26 thereof being formed of chromium or other high heat resisting metal as well as the casing 27 and shaft 28. This shaft extends through the heat insulating material 24, surrounding the casing, and is j ournaled, upon the outside of the casing, in bearings 29, which may be water cooled, as indicated by the pipes 30, a motor 31 being provided for driving the fan.

By forming the fan of this heat resisting metal `the impeller'will be able to resist the centrifugal action of the fan, at'high temperature, while the heat loss through the shaft will be very slight, and thus the journal portion of the shaft' will not overheat and in ay be easily cooled` by the water cooling p1pes.

In Fig. 1 is illustrated an application of the invention to a lurality of hoods in which the material may e passed through various stages of the heating, soaking and coolin periods, in different hoods, all controlle from the same heating and cooling means.

The duct 21, from the heating chamber, may be provided with a plurality of branch ducts 21, leading to the plurality of hoods, which for the purpose of illustration are indicated at A, B, C and D.

The duct 22, which leads to the fan an thence to the heating chamber, with a pluralityof branch-ducts 228L conl nectedto the several hoods.

A cooling chamber 32, provided with cooling coils 33 through which cold-water or the is provided like is passed, may be located upon the opposite side of the hoods from the heating chamber and is provided with a duct 34, commu- A damper 39 is provided in each branch l duct 21EL and 22 of the heating system and a similar damper 40, located at a 90 de ree angle thereto and arranged to be move in coordination therewith, is located in each branch duct 35 and 38 of the cooling system.

In order to coordinate the movement .of

eachpair of dampers 39 and 40 a mechanism such as illustrated in Fig. 5 may be provided. A rocker arm 41 is fixed upon the shaft 42 of each damper and provided, at its free end, with an elongated slot 43 engaging a pin 44 upon the screwshaft 45.

This shaft is mounted for longitudinal movement through the guide 46 and rotatable nut 47, being held against rotation in any suitable manner.

The nut 47 is mounted for rotation, being held against longitudinal movement in any suitable manner, and has fixed thereto a pinion 48 which may be driven, as by the pinion 49 upon the shaft of the motor 50.

With this construction, when one of the dampers of each pair is fully opened the other is fully closed and as the mechanism is operated the open damper is moved toward closed position and the closed damper toward open position until they reach a position such as shown in the ducts leading to the hood C where each damper is half-way open. Further movement of the mechanism will brin the dampers to the position shown in the hoo D, where the open damper has assumed the entirely closed position while the closed damper has assumed the entirely open position.

This provides for a control of the volume i of gas passing from either the heating or vcooling system through any one of the hoods and thus provides for control of the temperature of any desired hood, permittingy the ma- "terial in any hood tol be brought to the desired temperature Within the required period of time, held or soaked at this temperature for the required time and then cooled either slowly or rapidly as desired, all in a reducing or nonoxidizing atmos here and without handling or charging o the material from the time it starts to heat until it is fully cooled.

I claim:

1. A series of hoods of the character described and a system 'of heating consisting of an extraneously heated chamber and a cooling system consisting of an extraneously circulating a gas cooled chamber and means for controlling the amount of gases Within the hoods iiowing from each chamber through each hood.

2. An annealing apparatus comprising a plurality of hoods, a heating chamber eXtraneous to the hoods, a cooling chamber eXtraneous'to the hoods, a duct connecting each hood with the heating chamber in a closed circuit, a duct connecting each hood With the cooling chamber in a closed circuit, means for circulating a gas through each duct and means for independently controlling the flow of gas from any duct through any of the hoods.

3. An annealing apparatus comprising a plurality of hoods, a heating chamber ext-raneous to the hoods, a cooling chamber eXtraneous to the hoods, a duct connecting each hood With the heating chamber in a closed circuit, a duct connecting each hood With the cooling chamber in a closed circuit, means for through each duct and means for independently controlling the flow of gas from any duct through any of the hoods, the position of thev means controlling said iiow of gas being in spaced relationship with each other.

4. An annealing apparatus comprising a plurality of hoods, a heating chamber extraneous to the hoods, a cooling chamber eXtraneous to the hoods, a duct connecting each hood with the heating chamber in a closed circuit, a duct connecting each hood with the cooling chamber in a closed circuit, means for circulating a gas through each duct and means for independently controlling the flow of gas from any duct through any of the hoods, said control device for said ducts being arranged to operate in coordination with each other.

In testimony that I claim the above, I have hereunto subscribed my naine.

THADDEUS F. BAILY. 

